4,173 research outputs found
An ideal model of an assistive technology assessment and delivery process
The purpose of the present work is to present some aspects of the Assistive Technology Assessment (ATA) process model compatible with the Position Paper 2012 by AAATE/EASTIN. Three aspects of the ATA process will be discussed in light of three topics of the Position Paper 2012: (i) The dimensions and the measures of the User eXperience (UX) evaluation modelled in the ATA process as a way to verify the efficient and the evidence-based practices of an AT service delivery centre; (ii) The relevance of the presence of the psychologist in the multidisciplinary team of an AT service delivery centre as necessary for a complete person-centred assistive solution empowering users to make their own choices; (iii) The new profession of the psychotechnologist, who explores users needs by seeking a proper assistive solution, leading the multidisciplinary team to observe critical issues and problems. Through the foundation of the Position Paper 2012, the 1995 HEART study, the Matching Person and Technology model, the ICF framework, and the pillars of the ATA process, this paper sets forth a concept and approach that emphasise the personal factors of the individual consumer and UX as key to positively impacting a successful outcome and AT solution
Analysis of GeV-band gamma-ray emission from SNR RX J1713.7-3946
RX J1713.7-3946 is the brightest shell-type Supernova remnant (SNR) of the
TeV gamma-ray sky. Earlier Fermi-LAT results on low-energy gamma-ray emission
suggested that, despite large uncertainties in the background determination,
the spectrum is inconsistent with a hadronic origin. We update the GeV-band
spectra using improved estimates for the diffuse galactic gamma-ray emission
and more than doubled data volume. We further investigate the viability of
hadronic emission models for RX J1713.7-3946. We produced a high-resolution map
of the diffuse Galactic gamma-ray background corrected for HI self-absorption
and used it in the analysis of more than 5~years worth of Fermi-LAT data. We
used hydrodynamic scaling relations and a kinetic transport equation to
calculate the acceleration and propagation of cosmic-rays in SNR. We then
determined spectra of hadronic gamma-ray emission from RX J1713.7-3946,
separately for the SNR interior and the cosmic-ray precursor region of the
forward shock, and computed flux variations that would allow to test the model
with observations. We find that RX J1713.7-3946 is now detected by Fermi-LAT
with very high statistical significance, and the source morphology is best
described by that seen in the TeV band. The measured spectrum of RX
J1713.7-3946 is hard with index gamma=1.53 +/- 0.07, and the integral flux
above 500 MeV is F = (5.5 +/- 1.1)e-9 photons/cm^2/s. We demonstrate that
scenarios based on hadronic emission from the cosmic-ray precursor region are
acceptable for RX J1713.7-3946, and we predict a secular flux increase at a few
hundred GeV at the level of around 15% over 10 years, which may be detectable
with the upcoming CTA observatory.Comment: 9 pages, accepted for publication in Astronomy & Astrophysic
Excised acoustic black holes: the scattering problem in the time domain
The scattering process of a dynamic perturbation impinging on a draining-tub
model of an acoustic black hole is numerically solved in the time domain.
Analogies with real black holes of General Relativity are explored by using
recently developed mathematical tools involving finite elements methods,
excision techniques, and constrained evolution schemes for strongly hyperbolic
systems. In particular it is shown that superradiant scattering of a
quasi-monochromatic wavepacket can produce strong amplification of the signal,
offering the possibility of a significant extraction of rotational energy at
suitable values of the angular frequency of the vortex and of the central
frequency of the wavepacket. The results show that theoretical tools recently
developed for gravitational waves can be brought to fruition in the study of
other problems in which strong anisotropies are present.Comment: 8 pages, 9 figure
The extended structure of the remote cluster B514 in M31. Detection of extra-tidal stars
We present a study of the density profile of the remote M31 globular cluster
B514, obtained from HST/ACS observations. Coupling the analysis of the
distribution of the integrated light with star counts we can reliably follow
the profile of the cluster out to r~35", corresponding to ~130pc. The profile
is well fitted, out to ~15 core radii, by a King Model having C=1.65. With an
estimated core radius r_c=0.38", this corresponds to a tidal radius of r_t~17"
(~65pc). We find that both the light and the star counts profiles show a
departure from the best fit King model for r>~8" - as a surface brightness
excess at large radii, and the star counts profile shows a clear break in
correspondence of the estimated tidal radius. Both features are interpreted as
the signature of the presence of extratidal stars around the cluster. We also
show that B514 has a half-light radius significantly larger than ordinary
globular clusters of the same luminosity. In the M_V vs. log r_h plane, B514
lies in a region inhabited by peculiar clusters, like Omega Cen, G1, NGC2419
and others, as well as by the nuclei of dwarf elliptical galaxies.Comment: 9 pages, 6 figures. Accepted for publication in Astronomy &
Astrophysic
Massive young clusters in the disc of M31
We have studied the properties of a sample of 67 very blue and likely young
massive clusters in M31 extracted from the Bologna Revised Catalog of globular
clusters, selected according to their color [(B-V) < 0.45] and/or to the
strength of their Hbeta spectral index (Hbeta > 3.5 A). Their existence in M31
has been noted by several authors in the past; we show here that these Blue
Luminous Compact Clusters (BLCCs) are a significant fraction (>~ 15%) of the
whole globular cluster system of M31. Compared to the global properties of the
M31 globular cluster system, they appear to be intrinsically fainter,
morphologically less concentrated, and with a shallower Balmer jump and
enhanced absorption in their spectra.
Empirical comparison with integrated properties of clusters with known age as
well as with theoretical SSP models consistently indicate that their typical
age is less than ~2 Gyr, while they probably are not so metal-poor as deduced
if considered to be old. Either selecting BLCCs by their (B-V) colors or by the
strength of their Hbeta index the cluster sample turns out to be distributed
onto the outskirts of M31 disc, sharing the kinematical properties of the thin,
rapidly rotating disc component.
If confirmed to be young and not metal-poor, these clusters indicate the
occurrence of a significant recent star formation in the thin disc of M31,
although they do not set constraints on the epoch of its early formation.Comment: Submitted for publication in the Astronomical Journal. Aastex Latex
file of 22 pages, 12 figures and 3 table
The autoinflammatory diseases.
Summary The monogenic autoinflammatory syndromes are conditions caused by mutations of genes coding for proteins that play a pivotal role in the regulation of the inflammatory response. Due to their genetic nature, most of these disorders have an early onset. Clinically they are characterised by recurrent flares of systemic inflammation presenting most of the time as sudden fever episodes associated with elevation of acute phase reactants and with a number of clinical manifestations such as rash, serositis, lymphadenopathy and arthritis. Symptom-free intervals are characterised by complete wellbeing, normal growth and complete normalisation of acute phase reactants. Familial Mediterranean fever (FMF), mevalonate-kinase deficiency (MKD) and tumour necrosis factor (TNF) receptor-associated periodic syndrome (TRAPS) are the three monogenic disorders subsumed under the term periodic fevers, while a systemic inflammation dominated by a characteristic urticarial rash associated with a number of other clinical manifestations is typical of familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS) and chronic infantile neurological cutaneous and articular syndrome (CINCA). These diseases represent the clinical spectrum of different mutations of a gene named cold-induced autoinflammatory syndrome 1 (CIAS-1, or NLRP3) coding for a protein called cryopyrin. Hence these disorders are also known as cryopyrin-associated periodic syndromes (CAPS). Other conditions are characterised by typical granulomatous formations (granulomatous disorders). Blau's syndrome (familial juvenile systemic granulomatosis) presents with non-caseating granulomatous inflammation affecting the joint, skin, and uveal tract (the triad of arthritis, dermatitis and uveitis) and is associated with mutations of the NACHT domain of the gene CARD15 (or NOD2)
2MASS NIR photometry for 693 candidate globular clusters in M31 and the Revised Bologna Catalogue
We have identified in the 2MASS database 693 known and candidate globular
clusters in M31. The 2MASS J,H,K magnitudes of these objects have been
transformed to the same homogeneous photometric system of existing near
infrared photometry of M31 globulars, finally yielding J,H,K integrated
photometry for 279 confirmed M31 clusters, 406 unconfirmed candidates and 8
objects with controversial classification. Of these objects 529 lacked any
previous estimate of their near infrared magnitudes. The newly assembled near
infrared dataset has been implemented into a revised version of the Bologna
Catalogue of M31 globulars, with updated optical (UBVRI) photometry taken, when
possible, from the most recent sources of CCD photometry available in the
literature and transformed to a common photometric system. The final Revised
Bologna Catalogue (available in electronic form) is the most comprehensive list
presently available of confirmed and candidate M31 globular clusters, with a
total of 1164 entries. In particular, it includes 337 confirmed GCs, 688 GC
candidates, 10 objects with controversial classification, 70 confirmed
galaxies, 55 confirmed stars, and 4 HII regions lying within ~3 deg. from the
center of the M31 galaxy. Using the newly assembled database we show that the
V-K color provides a powerful tool to discriminate between M31 clusters and
background galaxies, and we identify a sample of 83 globular cluster
candidates, which is not likely to be contaminated by misclassified galaxies.Comment: 9 pages,5 figures,accepted for publication in Astronomy &
Astrophysics ASCII (commented) version of the tables 2,3,4 are available at
http://www.bo.astro.it/M3
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